Capacitors, which basically include two electrodes separated by a dielectric material, are used in a wide variety of electrical applications to accumulate and store an electrical charge. The development of electronic devices and circuits of reduced size has led to a need for significantly smaller capacitors having increased capacity per unit volume and high temperature capabilities.
Thin polymer films offer significant potential to produce smaller capacitors with increased capacity per unit volume. Such capacitors could therefore reduce the size of implantable devices, such as defibrillators, which currently use relatively large aluminum electrolytic capacitors in which the dielectric is aluminum oxide. Such large capacitors have an energy density of about 2 Joules/centimeter.sup.3 (J/cm.sup.3), which leads to capacitors of about 15 cm.sup.3. Smaller and lighter weight capacitors having higher energy densities (e.g., at least about 3 J/cm.sup.3) would provide significant advantage in decreasing the size of implantable devices.
One type of small, high energy density capacitor is referred to as a polymer multilayer (PML) capacitor. Examples of such capacitors are described, for example, in U.S. Pat. Nos. 4,499,520 (Cichanowski), 4,490,774 (Olson et al.), 4,954,371 (Yializis), 5,097,800 (Shaw et al.), and 5,032,461 (Shaw et al.). They are typically made by a vapor deposition process in which a polymerizable compound is vapor deposited onto a substrate and polymerized to form a polymer film. The polymerizable compounds are typically polymerized using electron beam or ultraviolet radiation. The polymer films are then typically metallized by either sputtering or vapor depositing a metal, such as aluminum. These processes (vapor coating, polymerizing, and metallizing) are repeated until the desired number of layers has been achieved.
Although there are a number of polymeric dielectric materials known for use in high energy density capacitors, such as PML capacitors, there is still a need for a wider variety of such materials that have the potential to produce smaller capacitors with increased capacity per unit volume. There is a particular need to produce small high energy density capacitors for use in high voltage defibrillators.
A number of patents and other documents have been reviewed in which polymeric dielectric materials are disclosed. Also, a number of patents have been reviewed in which capacitors, particularly PML capacitors, are disclosed. Although not admitted as prior art, these documents are listed among others in Table 1 below.
TABLE 1 LIST OF U.S. PATENTS AND OTHER DOCUMENTS Patent No. Inventor(s) Issue Date 2,017,537 October 15, 1935 Hoffman et al. 2,368,521 January 30, 1945 Clifford et al. 2,589,674 March 18, 1952 Cook et al. 3,278,500 October 11, 1966 Bailey, Jr. et al. 3,354,087 November 21, 1967 Bailey, Jr. et al. 4,490,774 December 25, 1984 Olson et al. 4,499,520 February 12, 1985 Cichanowski 4,513,349 April 23, 1985 Olson et al. 4,515,931 May 7, 1985 Olson et al. 4,533,710 August 6, 1985 Olson et al. 4,586,111 April 29, 1986 Cichanowski 4,613,518 September 23, 1986 Ham et al. 4,613,658 September 23, 1986 Mathias et al. 4,793,949 December 27, 1988 Mathias et al. 4,889,948 December 26, 1989 Mathias et al. 4,906,767 March 6, 1990 Mathias et al. 4,940,796 July 10, 1990 Mathias et al. 4,954,371 September 4, 1990 Yializis 4,985,522 January 15, 1991 Mathias et al. 4,999,410 March 12, 1991 Mathias et al. 5,026,802 June 25, 1991 Mathias et al. 5,032,461 July 16, 1991 Shaw et al. 5,094,759 March 10, 1992 Mathias et al. 5,097,800 March 24, 1992 Shaw et al. 5,134,175 July 28, 1992 Lucey 5,137,936 August 11, 1992 Akiguchi et al. 5,225,272 July 6, 1993 Poole et al. 5,440,446 August 8, 1995 Shaw et al. 5,519,087 May 21, 1996 Tang 5,554,120 September 10, 1996 Chen et al. 5,565,523 October 15, 1996 Chen et al. FR 740,410 1933 France DE 570,677 1933 Germany EP 146089 (abstract only) 1997 Europe JP 5140234 (abstract only) 1991 Japan Antonucci et al., "Synthesis of Novel Hydrophilic and Hydrophobic Multifunctional Acrylic Monomers", Polymers of Biological and Bio- medical Signficance, Chapter 16, pp. 191-201 (1994). Avci et al., "Ester Derivatives of a-Hydroxymethylacrylates: Itaconate Isomers Giving High Molecular Weight Polymers", Journal of Polymer Science, 32, pp. 2937-2945 (1994). "Barriers to Internal Rotation about Single Bonds", Physical Organic Chemistry, 6, pp. 1-81 (1968). Byun et al., "Improved Syntheses of Ethyl"-(Bromomethyl) Acrylate and 2-Methylene-1,3-Propanediol Via Ethyl "-(Hydroxymethyl) Acrylate", Tetrahedron Letters, 35, pp. 1371-1374 (1994). "Dielectric Constant and Leakage Current of Spin Cast Samples", Phase I Final Report II, Appendix A. Sigma Laboratories. Hillmyer, "The Preparation of Functionalized Polymers by Ring-Opening Metathesis Polymerization", California Institute of Technology, Pasadena, California 1995 Inamoto et al., "Revised Method for Calculation of Group Electro- negativities", Chemistry Letters, pp. 1003-1006 (1982). Jariwala et al., "Syntheses, Polymerization, and Characterization of Novel Semifluorinated Methacrylates, Including Novel Liquid Crystalline Materials", Macromolecules, 26, pp. 5129-5136 (1993). Kiyooka et al., "Reactivity of "-Metal (group 4) Esters. Lewis Acid Mediated Reactions of "-Triphenyltin Esters with Aldehydes and Acetals", The Chemical Society of Japan, 10, pp. 721-722 (1988). Mathias et al., "Cyclopolymerization of the Ether of Methyl "- (Hydroxymethyl)acrylate", Macromolecules, 21, pp. 545-546 (1988). Mathias et al., "New Difunctional Methacrylate Ethers and Acetals: Readily Available Derivatives of {character pullout}-Hydroxymethyl Acrylates", Macro- molecules, 20, pp. 2039-2041, (1987). Mathias et al., "Superfast Methacrylate Photomonomers: Ester Derivatives of Ethyl {character pullout}-Hydroxymethacrylates", Macromolecules, 28, pp. 8872-8874 (1995). "Organic Reactions: Volume V", John Wiley & Sons, Inc; New York, N.Y. (cover page and table of contents). "Polymers of Biological and Biomedical Significance", ACS Symposium Series (Division of Polymer Chemistry, Inc. at the 204.sup.th National Meeting of the American Chemical Society); Washington, D.C. (1994). Reed et al., "The Fundamentals of Aging in HV Polymer-film Capacitors", IEEE Transactions on Dielectrics and Electrical Insulation, 1, pp. 904-922 (1994). Semmelhack, J. Am. Chem. Soc., 103, 2427 (1981). Shing et al., "Practical and Rapid Vicinal Hydroxylation of Alkenes by Catalytic Ruthenium Tetraoxide", Angew. Chem., 33, pp. 2312-2313 (1994). Stansbury, "Observations Related to the Amine-Catalyzed Coupling Reaction of Aldehydes and Acrylates", Macromolecules, 26, pp. 2981-2982 (1993). Stansbury, "Difunctional and Multifunctional Monomers Capable of Cyclopolymerization", Macromolecules, 24, pp. 2029-2035 (1991). "The Chemistry of Acrylonitrile" American Cyanamid Company; Petrochemicals Department. New York, N.Y. (cover page and table of contents). Thompson et al., "Facile Synthesis and Polymerization of Ether Substituted Methacrylates", Polymer Journal, 27, pp. 325-338 (1995). Tsuda et al., "Cyclopolymerization of ether dimers of {character pullout}- (hydroxymethyl)acrylic acid and its alkyl esters: substitutent effect on cyclization efficiency and microstructures", Polymer, 35, pp. 3317-3328 (1994). Tsuda et al., "New Dicyano-Containing Cyclopolymers Having High Stereoregularity Derived from Dimethacrylmalononitrile", Macromolecules, 26, pp. 6359-6363 (1993). Tsuda et al., "Cyclopolymerization of Diallyl Malononitrile and the Thioether Dimer of Ethyl "-Chloromethylacrylate", Pure Appl. Chem., A31, pp. 1867-1879 (1994). Wells, "Group Electronegativities", Prog. Phys. Org. Chem., 6, pp. 111-145 (1968). Wideqvist, "New mononitriles of some dicarboxylic acids", Arkiv f r Kemi, 3, p. 59-67 (1951).
All documents listed in Table 1 above are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of Preferred Embodiments, and Claims set forth below, many of the devices and methods disclosed in these documents of Table 1 may be modified advantageously by using the teachings of the present invention.
It is a primary object of this invention to provide compounds that can be used to form polymeric dielectric materials, particularly thin dielectric films, in high energy capacitors, such as polymeric multilayer capacitors. This and other objects will be clear from the following description.